Foundations in Microbiology Sixth Edition Lecture PowerPoint to accompany Foundations in Microbiology Sixth Edition Talaro Chapter 1 The Main Themes of Microbiology Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Microbiology The study of organisms too small to be seen without magnification Microorganisms include: bacteria viruses fungi protozoa helminths (worms) algae

Branches of Study Within Microbiology Immunology Public health microbiology and epidemiology Food, dairy and aquatic microbiology Biotechnology Genetic engineering and recombinant DNA technology

Microbes are Involved in Nutrient production and energy flow Decomposition Biotechnology production of foods, drugs and vaccines Genetic engineering Bioremediation Infectious disease

Infectious Diseases Nearly 2,000 different microbes cause diseases. 10 B new infections/year worldwide 13 M deaths from infections/year worldwide

Characteristics of Microbes Procaryotes and eukaryotes procaryote – microscopic, unicellular organisms, lack nuclei and membrane-bound organelles eucaryote – unicellular (microscopic) and multicellular, nucleus and membrane-bound organelles Viruses acellular, parasitic particles composed of a nucleic acid and protein

Insert figure 1.5 basic cell and virus structures

Microbial Dimensions Procaryotes are measured in micrometers. Viruses in nanometers Helminths are measured in millimeters.

Insert figure 1.7 measurements

Historical Foundations of Microbiology 300 years of contributions by many Prominent discoveries include: microscopy scientific method development of medical microbiology microbiology techniques

Antonie van Leeuwenhoek (1632-1723) Dutch linen merchant First to observe living microbes Single-lens magnified up to 300X Insert figure 1.8

Insert figure 1.9 (a) microscope

Spontaneous Generation Early belief that some forms of life could arise from vital forces present in nonliving or decomposing matter (flies from manure, etc)

Scientific Method A general approach to explain a natural phenomenon Form a hypothesis - a tentative explanation that can be supported or refuted by observation and experimentation A lengthy process of experimentation, analysis and testing either supports or refutes the hypothesis.

Results must be published and repeated by other investigators. If hypothesis is supported by a growing body of evidence and survives rigorous scrutiny, it moves to the next level of confidence - it becomes a theory. If evidence of a theory is so compelling that the next level of confidence is reached - it becomes a Law or principle.

Discovery of Spores and Sterilization John Tyndall and Ferdinand Cohn each demonstrated the presence of heat resistant forms of some microbes. Cohn determined these forms to be endospores. Sterility requires the elimination of all life forms including endospores and viruses.

Development of Aseptic Techniques Dr. Oliver Wendell Holmes – observed that mothers of home births had fewer infections than those who gave birth in hospital Dr. Ignaz Semmelweis – correlated infections with physicians coming directly from autopsy room to maternity ward

Joseph Lister – introduced aseptic techniques reducing microbes in medical settings to prevent infections involved disinfection of hands using chemicals prior to surgery use of heat for sterilization

Pathogens and Germ Theory of Disease Many diseases are caused by the growth of microbes in the body and not by sins, bad character, or poverty, etc. Two major contributors: Louis Pasteur and Robert Koch

Louis Pasteur (1822-1895) Insert figure 1.11 Showed microbes caused fermentation and spoilage Disproved spontaneous generation of microorganisms Developed pasteurization Demonstrated what is now known as Germ Theory of Disease Developed a rabies vaccine Insert figure 1.11

Robert Koch (1843-1910) Insert figure 1.12 Established Koch’s postulates - a sequence of experimental steps that verified the germ theory Identified cause of anthrax, TB, and cholera Developed pure culture methods Insert figure 1.12

Taxonomy: Organizing, Classifying and Naming Living Things Formal system originated by Carl von Linné (1701-1778) Concerned with: classification – orderly arrangement of organisms into groups nomenclature – assigning names identification – discovering and recording traits of organisms for placement into taxonomic schemes

Levels of Classification Domain - Archaea, Bacteria & Eukarya Kingdom - 5 Phylum or Division Class Order Family Genus species

Naming Micoorganisms Binomial (scientific) nomenclature Gives each microbe 2 names: Genus - noun, always capitalized species - adjective, lowercase Both italicized or underlined Staphylococcus aureus (S. aureus) Bacillus subtilis (B. subtilis) Escherichia coli (E. coli)

Evolution - living things change gradually over millions of years Changes favoring survival are retained and less beneficial changes are lost. All new species originate from preexisting species. Closely related organism have similar features because they evolved from common ancestral forms. Evolution usually progresses toward greater complexity.

3 Domains Bacteria - true bacteria, peptidoglycan Archaea - odd bacteria that live in extreme environments, high salt, heat, etc. Eukarya- have a nucleus and organelles

Insert figure 1.15 Woese-Fox System